"Before Elvis, there was nothing," John Lennon once said. An overstatement, of course, but Elvis Presley's ascendance to superstardom in the mid-1950s kicked off a musical and social revolution whose impact has yet to abate. After the charming young man from Tupelo, Mississippi was discovered by Sun Records honcho Sam Phillips, the wise studio owner took Presley under his wing, leading to the landmark recording of his first single, "That's All Right (Mama)." The rest, of course, is well-documented history, with Elvis going on to conquer the pop charts, the box office, and beyond. He truly was the King, and his blend of country, pop, and R&B became the cornerstone of rock & roll.